Semiconductor device

Abstract

A semiconductor device which is capable of operating at an operation frequency “f”, includes a substrate, a first element unit and a second element unit. The substrate has a thermal diffusion coefficient “D”. The first element unit is formed on the substrate. The first element includes a first active element. The second element unit is adjacent to the first element unit on the substrate. The second element includes a second active element. The second active element acts on a different timing from the first active element. Moreover, a distance of between a first gravity center of the first element unit and a second gravity center of the second element unit is equal to or less than twice of a thermal diffusion length (D/πf) 1/2 .

What is claimed is: 
     
       1. A wide-gap semiconductor device, the device comprising:
 a substrate having a thermal diffusion coefficient “D”; 
 a plurality of first element units formed on the substrate, the first element units each including a first active element; and 
 a plurality of second element units, the second element units each including a second active element, the second active element acting on a different timing from the first active element each of the first element units and each of the second element units being arranged alternately, wherein 
 a distance of between a first gravity center of the first element unit and a second gravity center of the second element unit is equal to or less than twice of a thermal diffusion length (D/(πf)) 1/2 , excluding zero, so that the first element units and the second element units are spatially separated from each other, and wherein 
 any two of the first element units do not share a first electrode or a second electrode with each other, and wherein 
 any two of the second element units do not share the first electrode or the second electrode with each other, and wherein 
 the first electrode and the second electrode are included in each of the first element units and each of the second element units, and wherein 
 the thermal diffusion length being within a range when the semiconductor operates at a frequency “f’, and the frequency “f’ being between 10 kHz and 1 MHz, and wherein 
 the first active element units are transistors and the second active elements are diodes. 
 
     
     
       2. The device of  claim 1 , wherein a thickness of the substrate is equal to or smaller than the thermal diffusion length. 
     
     
       3. The device of  claim 1 , wherein the second active element is inactivated while the first active element is activated. 
     
     
       4. The device of  claim 1 , wherein the first active element and the second active element are wide-gap semiconductors. 
     
     
       5. The device of  claim 4 , wherein the wide-gap semiconductor is a nitride semiconductor or a silicon carbide. 
     
     
       6. A wide-gap semiconductor device, the device comprising:
 a substrate having a thermal diffusion coefficient “D”; 
 a plurality of first element units formed on the substrate, the first element units each including a first active element; and 
 a plurality of second element units, the second element units each including a second active element, the second active element acting on a different timing from the first active element, each of the first element units and each of the second element units being arranged alternately wherein 
 each of the first element units and the second element units are repeatedly arranged with a cycle, a half of the cycle being equal to or less than twice of a thermal diffusion length (D/(πf)) 1/2 , the cycle excluding zero, so that the first element units and the second element units are spatially separated from each other, and wherein 
 any two of the first element units do not share a first electrode or a second electrode with each other, 
 any two of the second element units do not share the first electrode or the second electrode with each other, and wherein 
 the first electrode and the second electrode are included in each of the first element units and each of the second element units, and wherein 
 the thermal diffusion length being within a range when the semiconductor operates at a frequency “f’, and the frequency “f’ being between 10 kHz and 1 MHz, and wherein 
 the first active element units are transistors and the second active elements are diodes. 
 
     
     
       7. The device of  claim 6 , wherein a thickness of the substrate is equal to or smaller than the thermal diffusion length. 
     
     
       8. The device of  claim 6 , wherein the second active element is inactivated while the first active element is activated. 
     
     
       9. The device of  claim 6 , wherein the first active element and the second active element are wide-gap semiconductors. 
     
     
       10. The device of  claim 9 , wherein the wide-gap semiconductor is a nitride semiconductor or a silicon carbide.